Positional obstructive sleep apnea and periodic limb movement during sleep: A large multi-center study.

ABSTRACT

Objectives: The relationships among positional obstructive sleep apnea (POSA), obstructive sleep apnea (OSA), and periodic limb movement during sleep (PLMS) are unclear. We analyzed these relationships according to OSA severity and explored the underlying mechanisms. Methods: We retrospectively reviewed 6,140 eligible participants who underwent full-night diagnostic polysomnography in four clinical centers over a period of 5 years with eventsynchronized analysis. The PLMS index (PLMI) and periodic limb movements with arousal index (PLMAI) were evaluated. The effects of POSA on the PLMI, PLMAI, and PLMS were analyzed according to OSA severity. Results: The mean PLMI and PLMAI, as well as PLMS prevalence, were significantly lower in those with severe OSA than in those with mild and moderate OSA. The mean PLMI was higher in mild OSA group than in control group. The mean PLMI (4.80 ± 12.71 vs. 2.59 ± 9.82 events/h, p < 0.001) and PLMAI (0.89 ± 3.66 vs. 0.53 ± 3.33 events/h, p < 0.001), and the prevalence of PLMS (11% vs. 5.3%, p < 0.001) were higher in patients with POSA than patients with non-POSA. This trend was particularly marked in severe OSA group (OR 1.55, 95%CI [1.07-2.27]) and less so in mild (OR 0.56, 95%CI [0.30-1.03]) and moderate (OR 1.82, 95%CI [0.99-3.34]) OSA groups. Conclusion: The POSA group tended to have a higher prevalence of PLMS, particularly in those with severe OSA. If PLMS is prominent, diagnosis and treatment of POSA and OSA may be considered.